1. Field of the Invention
The present invention relates to a method for manufacturing a wiring board through a process that peels a protective film from a substrate having an insulation material layer protected by the protective film, and to a film peeling apparatus for use in peeling the protective film from the substrate having the insulation material layer protected by the protective film.
2. Description of the Related Art
Conventionally, a process of manufacturing a wiring board includes a process of forming an insulation material layer on the surface of a substrate. Examples of such a process include a step of laminating a photosensitive resist film, a photosensitive, or a thermosetting interlayer insulation material film on the surface of the substrate. The surface portion of the insulation material layer is, for example, covered with a carrier film made from PET (polyethylene terephthalate). Each carrier film is laminated on the main surfaces of each substrate. Therefore, it is necessary to peel the carrier film from the surface of the insulation material layer prior to processing the bonded insulation material layer.
Further, as another example of the process for forming the insulation material layer on the surface of the substrate, there is a process that forms the insulation material layer by repeating an application and a drying process of a liquid resist to the surface of the substrate. Since the surface portion of the insulation material layer may be adhesive to some degree even after being dried, it is necessary to cover it with, for example, a protective film made from PET etc. Similar to the carrier film, each protective film is also laminated on the main surfaces of each substrate. Therefore, similar to the case of peeling the carrier film, it is necessary to peel the protective film from the surface of the insulation material layer beforehand in order to develop the insulation material layer after exposure thereof.
As a conventional method for peeling such a carrier film or a protective film, for example, to form a floating part on the film, it is suggested that the film be scratched (e.g., see Patent Document 1) by moving the film in a surface direction of the film while rotating a knurling roll. Further, another proposed method is for a film pressing member to be moved along the surface direction of a film so as to lift the film to thereby form a floating part thereon (e.g., see Patent Document 2).
[Patent Document 1] Japanese Patent Application Laid-Open (kokai) No. 2000-86080 (FIG. 1 etc.)
[Patent Document 2] Japanese Patent Application Laid-Open (kokai) No. H10-324454 (FIG. 2 etc.)
3. Problems to be Solved by the Invention:
However, since it would be necessary to perform a peeling operation the same number of times as the number of substrates (and twice the number when films are laminated on both sides of a substrate) when a film provided on the substrate is to be peeled, efficiency of the peeling operation cannot be improved upon. Further, since the quantity of peeled films will be the same as the number of substrates or greater, the collection of separated films will be complicated.
Still further, if an excessive force is applied to a film when a knurling roll or a film pressing member is moved, it will lower yield due to the high probability that an insulation material layer or the substrate might be damaged. Still even further, the insulation material layer is formed of a fragile material which is easily damaged, even by a little scratch. Thus, a part of the insulation material layer is likely to collapse and become debris, thereby creating foreign particles. Moreover, if the foreign particles adhere to the insulation material layer, the thickness of the insulation material layer will not be uniform, which will also be a factor leading to lowering of yield.